Vacuum microelectronic field emission devices are known. Prior methods for realization and operation of field emission devices includes forming an electron emitter, for emitting electrons, as a substantially conical/wedge shaped structure disposed within a cavity and having a conductive accelerating electrode disposed peripherally about the cavity. Application of a suitable potential between the accelerating electrode (gate electrode) and the electron emitter will induce electrons to be emitted from the electron emitter. In practice this field emission device electron emitter is operated in concert with a distally disposed anode, for collecting electrons, defining an intervening region therebetween. In order that emitted electrons may arrive at and be collected by the anode the field emission device is operated in an evacuated environment on the order of 10.sup.-7 to 10.sup.-9 Torr. At higher residual pressures, and in the presence of electron emission, substantial ionization of gaseous molecules may take place. Additionally, desorption of contaminants from the surfaces of the electron emitter and the accelerating electrode may provide for a significantly increased local residual gas pressure in the region of the cavity. It is a common shortcoming of known vacuum microelectronic field emission devices that such a local increased residual gas gives rise to destructive breakdown of the field emission device observed as an arc discharge often resulting in a short circuited field emission device and always in the destruction of the electron emitter.
Accordingly, there exists a need for a microelectronic field emission device apparatus and method for realization which overcomes at least some of these shortcomings.
Accordingly, it is a purpose of the present invention to provide an insulated gate field emission device wherein the possibility for gate to electron emitter destructive discharge is removed or substantially reduced.
It is a further purpose of the present invention to provide an insulated gate field emission device wherein a previously unknown electric field enhancement mechanism is provided.